1. Field of the Invention
The present invention relates to an attachment method of a high-voltage condenser used in a high-voltage circuit of a high-frequency heating apparatus and attachment fittings for the high-voltage condenser.
2. Description of the Related Art
In a high-voltage circuit of a high-frequency heating apparatus, a high-voltage condenser has been used till now in order to obtain half-wave voltage double commutation. As its attachment method, there are methods shown in FIGS. 10, 11 and 12, 13.
In an example shown in FIGS. 10 and 11, below a resin-made orifice 1, a high-voltage condenser 3 is held between the orifice and a half-oval attachment fittings 2, and the attachment fittings 2 is fixed with a screw from a side of a back plate 4.
In an example shown in FIGS. 12 and 13, a high-voltage condenser 6 is held by an attachment fittings 7, and the attachment fittings 7 is fixed to a flat portion 8A of a bottom plate 8 with a screw 9 from the inside.
However, in the example shown in FIGS. 10 and 11, since the high-voltage condenser 3 is attached below the orifice 1, the size of the orifice 1 becomes large, so that there is a problem in resources-reduction. Further, since the width of the orifice 1 must be made larger than the length (L1) of the high-voltage condenser 3, there are problems in size-reduction and space-reduction of the high-frequency heating apparatus. Further, since a terminal portion 3A of the high-voltage condenser 3 is close to the metal-made back plate 4, an outer frame 10 and a bottom plate 11, sufficient insulation distance cannot be secured. Therefore, it is necessary to stick an insulating sheet 12 on the inside of the outer frame 10 or coat a lead wire 13 connecting to the terminal portion 3A of the high-voltage condenser 3 with an insulating tube 14, so that there are also problems in resources-reduction, assembly efficiency, and price. Further, since the high-voltage condenser 3 is placed below the orifice 1, it does not receive wind from a cooling fan 15 at all but is cooled naturally, so that there is a problem in level-up of output.
Further, in the example shown in FIGS. 12 and 13, the high-voltage condenser 6 is held by the oval attachment fittings 7, and the attachment fittings 7 is fixed onto the flat portion 8A of the bottom plate 8 with the screw 9 from the inside. However, similarly to in the example shown in FIG. 10, attachment dimension of the length (L2) of the high-voltage condenser 6 is required, so that there are problems in size-reduction and space-reduction of the high-frequency heating apparatus. Further, since a insulation distance between the high-voltage condenser 6 and a metal-made back plate 16 or an outer frame 17 cannot be sufficiently secured. Therefore, it is necessary to stick an insulating sheet 18 on the inside of the outer frame 17 or coat a lead wire 19 connecting to the high-voltage condenser 6 with an insulating tube 20, so that there are also problems in resources-reduction, assembly efficiency, and price. Further, since the attachment fittings 7 holding the high-voltage condenser 6 is fixed to the flat portion 8A of the bottom plate 8 with the screw 9, the screw 9 protrudes downward from the bottom plate 8. Therefore, when a user handles the high-frequency heating apparatus, the screw 9 touches his hand, so that an unpleasant feeling or a sense of incompatibility in appearance is given to him.
In order to solve the problems in size-reduction, space-reduction, resources-reduction, assembly efficiency, and price, in the first aspect of the invention, a part of a body of a high-voltage condenser is arranged between a heating chamber bottom wall and a bottom plate.
A heating chamber of a high-frequency heating apparatus includes side plates, a lower plate, an upper plate, a front plate and a back plate. Flange portions are formed respectively at the lower portions of the front plate and the back plate, and a bottom plate is fixed to the flange portions of the front plate and the back plate. Apart of the body of the high-voltage condenser is arranged between the lower plate constituting the heating chamber and the bottom plate, the high-voltage condenser is held by an attachment fittings, and the attachment fittings is fixed onto the bottom plate.
According to the first aspect, since a part of the body of the high-voltage condenser is thus arranged between the heating chamber lower plate and the bottom plate, the dimension regulated by the length of the high-voltage condenser can be reduced, so that size-reduction and space-reduction of the high-frequency heating apparatus are possible.
Further, an outer frame is attached so as to cover the front plate and the back plate that are attached to the front and the back of the heating chamber. Since by arranging a part of the body of the high-voltage condenser between the heating chamber lower plate and the bottom plate, the insulation distance between a terminal portion of the high-voltage condenser and the outer frame can be sufficiently secured, it is not necessary to-stick an insulating sheet on the outer frame, so that the problems in resources-reduction, assembly efficiency, and price can be also solved.
In order to solve the problems in resources-reduction, assembly efficiency, and price, in the second aspect of the invention, flange portions are formed respectively at the lower ends of a front plate and a back plate that form a heating chamber, a bottom plate is fixed to the flange portions of the front plate and the back plate, and valley portions drawn downward in order to attach leg rubbers are formed in a bottom plate. A terminal portion of a high-voltage condenser is arranged on the valley portion, and the high-voltage condenser is held through an attachment fittings at a mountainous portion formed at the bottom plate.
According to the second aspect, the leg rubbers for supporting the high-frequency heating apparatus are attached apart from the back plate and the outer frame so as not to overturn in view of the weight balance of the high-frequency heating apparatus, and the terminal portion of the high-voltage condenser is arranged on the valley portion of the bottom plate formed in order to attach the leg rubber. Hereby, the insulation distance between the terminal portion of the high-voltage condenser and the metal-made back plate or outer frame can be secured sufficiently. Further, since the terminal portion of the high-voltage condenser is arranged on the leg rubber attachment portion formed by drawing the bottom plate downward, the insulation distance between the bottom plate and the terminal portion of the high-voltage condenser can be also sufficiently secured. Therefore, it is not necessary to stick an insulating sheet on the inside of an outer frame or to cover a lead wire with an insulating tube because of shortage of the insulation distance produced in the conventional examples, so that the problems in resources-reduction, assembly efficiency, and price can be solved.
In order to remove the unpleasant feeling at the handling time or a sense of incompatibility in appearance in the examples, in the third aspect of the invention, flange portions are formed respectively at the lower ends of a front plate and a back plate that form a heating chamber, the front and the back of a bottom plate is fixed to the flange portions of the front plate and the back plate, a high-voltage condenser is held by an attachment fittings, the attachment fittings is fixed to a mountainous portion formed at the bottom plate with a screw from the inside of the bottom portion, and the screw is surrounded by valley portions formed in the bottom plate more deeply than the length of the screw.
According to the third aspect, though the screw for holding the high-voltage condenser is tightened from the inside of the bottom plate and protrudes downward from the bottom plate, since it is surrounded by the valley portions drawn downward more deeply than the length of the screw, it is possible to solve such the problems that the unpleasant feeling is given by touch of the screw on user""s hand at the carrying time of a high-frequency heating apparatus or a sense of incompatibility in appearance is given because the screw can be seen from the downside of the valley portion of the bottom plate.
In order to solve the problems in resources-reduction, assembly efficiency, price, and cooling efficiency of high-voltage condenser, in the fourth aspect of the invention, a magnetron is fixed to a magnetron attaching plate fixed to a heating chamber sidewall, a bottom plate is attached to lower ends of a front plate and a back plate that form a heating chamber, a high-voltage transformer is attached on the bottom plate, a cooling motor having a cooling fan is attached to the back plate, a high-voltage condenser is arranged at a position nearer to the windward of the cooling fan than the magnetron and the high-voltage transformer, and the high-voltage condenser is held through an attachment fittings on the magnetron attaching plate.
According to the fourth aspect, since the high-voltage condenser is thus held through the attachment fittings on the magnetron attaching plate, it can be held at a position sufficiently distant from the metal-made back plate and bottom plate. Therefore, it is possible to solve the problem in resources-reduction, assembly efficiency, and price that a lead wire is covered with an insulating tube. Further, since the high-voltage condenser is arranged at the position nearer to cooling fan than the high-voltage transformer and the magnetron hereby to forcedly receive wind from the cooling fan, cooling performance of the high-voltage condenser improves, so that the problem in level-up of output can be solved.
In order to solve the problems in size-reduction, space-reduction, resources-reduction, assembly efficiency, and price, according to the fifth aspect of the invention, a drawn portion protruding backward is formed at a back plate constituting a heating chamber, a back portion of a high-voltage condenser is inserted into this drawn portion, a terminal portion side of the high-voltage condenser is held by an attachment fittings, the attachment fittings is fixed to a bottom plate, and the high-voltage condenser is arranged in the depth direction of the high-frequency heating apparatus.
According to the fifth aspect, since high-voltage condenser is thus held in the depth direction of the high-frequency heating apparatus, it is possible to solve the problem that the size-reduction and space-reduction of the high-frequency heating apparatus are impossible due to the length of the high-voltage condenser. Further, it is easy to secure the insulation distance between the high-voltage condenser and the metal-made back plate, the bottom plate or an outer frame, and it is possible to solve such the problem in resources-reduction, assembly efficiency, and price that an insulating sheet or an insulating tube is used because of shortage of the insulation distance.